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METHOD OF AND APP T. B. DIXON.

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APPLICATION FILED IIILY I9. ISIS. 1,1 93,999. Patented Aug. 8,1916.

I5 SHEETS-SHEET l5- UNITED STATES PATENT OFFICE.

THOMAS BULLITT DIXON OF NEW YORK, N. Y.

NIETHOD-OF AND APPARATUS FOR TRANSFORMING MOTION INTO ELECTRICAL WA\ ES OR IMPULSES.

Application filed July 19, 1915.

To all whom it may concern Be it known that I, THOMAS B. DIXON, citizen of the United States of America, and a resident'of New York. in the county of New-'York and State of New York, have invented certain new and useful Improvements in Methods of and Apparatus for 'lransforming Motion into Electrical \Vaves or impulses. of which the following is a spccification.-

)ly invention relates to a method of and apparatus for producing current fluctuations in' an electric circuit by means of the action of radiant energyusually a beam or beams of lighton a radio-electric sensitive element or elements, such for example as selenium cells'f'also a method of and apparatus for transforming motion into electrica -waves or impulses, and for ampli tying electrical.impulses, by means of the action of radiant energy u on radio-elec tro-scnsitivc means.

My invention consists in a method of and means for employing a plurality of beams of radiantenergy. derived if desired from .a single source. and in general. acting upon the same radio-electi'o-sensitive element or group of such elements. theaction and motion of all of such beams being controlled. by the same primary actuating means (which usually is-a reflector. operated by a galvanometer. or by a phonograph or telephone diaphragm or other suitable means).

Other features of my invention will be pointedout hereafter.

The objects of my invention are to obtain greater etliciency of utilization of radiant energy specifically. lightin the. production of current fluctuations in an electric circuit. in the transforming of motion into electrical \'2l\'CS'.-()[' impulses. and in the amplificatii-m of electrical impulses: to permit the cllicient cooperative utilization of" a plu rality of light bcamsdcrived from a single source: .to permit the etiicient cooperative \ltlllZfltlOn of-light beams taken from substantially all sides of a single source of illumination to make possible the concentrationoi a pluralitv of light beams. whether from the same source or from separate sources. upon a single primary-actuatingdevice reflector. the subsequent scpz'iration of such light beams. and their final concentration upon the same railio-clcctrosensitivc device or a group or groups of such Specification of Letters Patent.

" Patented Aug. 8, 1916.

Serial No. 4Q,694.

devices; to permit the use, with etlicient results, in radio-electric relays, of sources of illumination such as Nernst glowers, incan-- descentfilaments, etc, in lieu of the more powerful but less steady are light; and to make the apparatus simple, relatively compact, and highly efficient.

Other objects of my invention will appear hereafter.

It has been proposed heretofore to produce current fluctuations in an electric circuit by varying the action of radiant energy (usually a light beam) upon one or more radio-electrosensitive devices (usually selenium cells), by means of a primary actuating device (usually a mirror actuated by a. ga'lvanometer coil) the beam oflight being usually caused to move across such selenium cell or cells by the motion of the primary-actuating-device reflector. and so varying the resistance of the selenium cell or cells, and thereby producing electrical "waves or impulses in an electric circuit in which such selenium cell or cells is or are included. which electrical waves or'impulscs are capable of operating sensitive relays and other sensitive electrical apparatus. The efficiency of such apparatus is very largely dependent upon the intensity of illumination of the selenium cell or cells by the light beam. and optical conditions have been thoughtto preclude the successful use of more than one light beam or pencil from one or more sources of illumination for the same selenium cell or group-of cells: 'furthermore. optical conditions have heretofore seemed to make necessary that this light beam or pencil shall be of very restricted dimensions as compared with the total light emitted by the source of illumination. The present strongest source of illumination which produces its light within such small dimensions as are required for accurate pro iection. is the electric arc: and while I have used the electric arc with success. still its use open to the objection that it is not as steady as is desirable: and furthermore. the carbon electrodes require frequent replacement. Other sources of illumination. such as Yernst 'lowers. tungsten and other high-efliciency incandescent lamp filaments. ctc.. otter a much more steady illumination. together with a more concentrated source of illumination. but are not as strong sources of illumination as is the electrical shall be concentrated upon the same mov-- ing reflector (though as hereinafter described I have used with success, a plurality of reflectors mounted to move together; but the number of reflectors which can be so mounted to move together and mounted with the delicacy and low inertia factor required for apparatus of this sort is at best small as compared with the total number of light beams which I have found may be derived and utilized from a single source of illumination). Even if a number of reflectors be used, it is practically necessarv (except as stated hereinafter) thatthey be mounted to move about the same axis; therefore, for most purposes, the conditions are much the same, whether a. plurality of reflectors be used, or whether a single reflector be used, with .all the light pencils concentrated upon that single reflector. Since it a number of light pencils be projected upon a single re- 'flector (or upon a plurality of reflectors mounted to oscillate about a ommon axis) those'pencils of light must be taken from different portions of the-sphere of illumination of the source of illumination, and therefore are necessarily divergent relatively, it

follows that these-pencils of light must be directed convergently (relative to one another) upon the reflector or reflectors; and in consequence these pencils of light will be reflected divergently from that reflector; a conditionwhich has in the past, apparently prevented their subsequent concentration upon a single selenium cell or group of selenium cells; at least I am not aware that any other person has thought of using such a plurality of pencils of light, derived from a single'source or plurality ,of sources of illumination, projected convergently (relatively to one another) upon the same primary-actuating-device reflector, and thence reflected divergently, and then converged upon a single selenium cell or group of cells. I have found, however, thatit is quite possible to concentrate such divergent reflected light pencils upon a single selenium cell or cells, and to do so notwithstanding lateral movament of such reflected light pencils, due tb motion of the primary-actuating-reflector. Thereby I have been able to obtain, from asingle source of illumination, an effective illumination of the selenium cell or cells, many times greater than that which it has been thought to be possible to obtain from such single source of illumination,

heretofore. Y Moreover, I have been able to accomplish this result and yet to keep all of the pencils of light of substantially the same total length from the source of illumination to the selenium cells; a condition which is sometimes desirable.

Thereare various other factors which have heretofore interfered with obtaining anything approaching the high efiicieney and high rate of telegraphic transmission made possible by the apparatus hereinafter described. For example, much difficulty has been experienced in the past in finding means to so control the radiant energy that a sufiicien tly large displacement or other variation of such energy results from the desirably small variation in the primary actuating device. Obviously, it is important that the primary actuating device shall have very small movements; for it is here only that inertiaexists in the apparatus; and obviously the apparatus is the more delicate and the more capable of rapid operation as the inertia. factor is less. In fact, the permissible inertia of this primary actuating device or reflector is the starting point and chief limiting factor for optical calculations in connection with the designing of efiicient apparatus of this character.

Since, with a radio-electro-sensitive element influenced by the motions of a light beam, the electrical variation is proportional to the surface the illumination of which is varied by a given movement of that beam, it follows that the best distribution of the surface area of the selenium cell or other radio-electro-sensitive device, is had when the cell has either greater height than breadth; (the light beam in such case vibrating in a horizontal plane) or when the cell has greater breadththan height (in which case the light beam vibrates in a vertical plane). Correspondingly, the primary actuating device reflector from which the light beam is reflected and thereby caused to'move across the surface of such selenium cell or cells will commonly have great length (in the directionof itsaxis of oscillation) as compared with its breadth; this condition permitting the inertia of that reflector to beminimum. Another reason for the use of a plurality of light beams is that I have found that for optical reasons it is impossible to project from a single mirror of the small Size desired in order that its inertia factor may be small, one beam of light only which is free to move, and also has the requisite length from the movable reflector to the selenium cell or cells and cross-section and intensity to enable the radio-electric-relay to meet all the requirements desired with respect to such a relay. And there are still other factors which make the use of a plurality of light beams, controlled by a single primaryactuatingdra wing.

device reflector and sweeping across the same selenium cell or group of cells a vast improvement over the'use of a single light beam only. i

I will now proceed to describe my invention with reference to the accompanying drawlngs and will then point out the novel features in claims.

In the drawings: Figure 1 is a diagrammatic view illustrating schematically one form of apparatusembodying the apparatus portion of my invention and adapted for carrying out the method portion of my invention. Fig. 2 is a diagram showing two radiofelectro-sensitive elements (usually selenium cells) with circuits therefor, and the magnet poles and armature coils of an instrument of the nature of a galvanometer to be actuated by variation of resistance of those radio-electrosensitive devices; the viewalso showing the beam of radiant en orgy in its normal or middle position on such radio-electro-sensitive device. Fig. 2 is a diagrammatic view showing the two windings of the galvanometer coil 10 more clear] y than said windings are shown in Fig. 2. Figs. 3 and -.l are respectively a vertical section and an end view of one of thesegmental condensing lenses employed in the arrangement shown in Fig. 1, and 'also in arrangements shown in various other figures ot' the Figs. 5 and'G are respectively a vertical section and a front elevation of the s )herically-curved reflectors employed back of the source of illumination. in the arrangcment shown in Fig. 1. and in arrangements shown in various other figures of the drawings. Figs. 7 and 8 are respectively a vertical section and an end view of a segmental meniscus condensing lens which may be employed in lieu of the plano-convex condensing lens shown in Figs. 3 and 4. Fig. 9 is a view similar to Fig. 1, but illustrating an alternative arrangement of apparatus. Fig. 10 is a further view similar to Fig. l, but illustrating a still further alternative arrangement of apparatus. Fig. 11 is a view similar to Fig. 1. but illustrating the use for th concentration of certain of the light pencils upon the primary-actuating device. of retracting prisms. in lieu of the totalreflect ing prisms shown in Figs. 1 and 9. Fig. 12 is a diagrammatic view illustrating the use of a primary actuating device reflector having two reflecting surfaces, in connection with means for taking light pencils from all sides of a source of illumination and (30110011 trating such pencils finally upon a single radio-electro-sensitivedevice or group of such devices. Fig. 13 is a view similar to Fig. 12, except that a plurality of sources of illumination are shown, the light pencils from such several sources being concentrated upon the same radiofelectro sensitiye device or group of such devices. Plg. 14 1s a fragmentary diagrammatic view, similar to Fi 13, except that the secondary reflectors are shown arranged to divide. the various reflected light pencils 8 into groups, and to project the pencils of each group upon a radio-elect1 -o-sensitive device or group of such devices, different from that upon which each of the other group of pencils is projected. Fig. 15 is a diagrammatic view illustrating means for dividing the light pencils by means of groups of secondary reflectors arranged angularly. Fig. 16 is a fragmentary diagrammatic view illustrating an alternative arrangement of angularly arranged secondary reflectors which may be employed in lieu. of the arrangement shown in Fig. 15. Fig. 17 is an elevation and partial vertical section of one of the galvanometer-coil and primaryactuating-device reflector mountings which may be employed; Fig. 18 is a top view and partial horizontal section of the said mounting; Fig. 19 is a tragmentaiy elevation of a portion of such mounting, the section being taken on a plane at right angles to that of Fig. 17: and Fig. 20 shows a front view of the galvanometer coil and associated parts. Fig. 21. shows a diagrammatic perspective elevation of an alternative and simplified arrangement of reflectors and light pencils which, may be employed. Fig. 22 is a fragmentary diagrammatic view illustrating the use of angularly arranged reflectors for combining upon one group of radio-electro-sensitive devices. the two tiers of light pencils illustrated in Fig. 21. Fig. 23 is a diagrammatic perspective view illustrating a further simplified arrangement of reflectors and light pencils. Fig. 21 is a further diagran'imatic view illustrating in plan another arrangement of reflectors and light pencils which may be employed. Fig. 25 shows, more or less diagrammatically a front elevation of a primar -actuating-device reflector arrangement which may be employed, comprising a plurality of reflectors. arranged side by side, and having independent suspensions, but which reflectors nevertheless are arranged to move together; and Fig. 26 shows a horizontal section on the line of Fig. Fig. :27 shows a side elevation of the parts shown in Fig. 25. Figs. 28%30 inclusive are diagrams illustrating various arrangements of selenium cell circuits whereby a light pencil or plurality of light pencils acting difl'ercntially on selenium cells affects the coil of a siphon recorder or other receiving or re-transmitting apparatus and Fig. 31 is a similar diagram showing a light beam arranged to act on one or another ot' two selenium cells alternatively. Figs. 32%31 in.- clusive illustrate the mechanical structure of one mounting for a plurality of segmental lenses; Fig. 32 showing a top view and partial horizontal section. Fig. 33 showing a. fragmentary sideelevation, and Fig. 84. a

g of such cells, to be affected by 32. Fig. 35 is a diagram illustrating the action of the light pencils in connection with the lens mounting such as shown in Figs. 3243i inclusive; Fig. tion. and Fig. 35* a front elevation of one of a plurality of segmental reflectors which may be used in lieu of a unitary reflector 9 shown in Fig. 35; and Fig. 35 is a top view showing the arrangement of such segmental reflectors in connection with the source of illumination. and segmental condensing lenses of Fig. 35. Figs. 36, 37 and 38 are diagrams illustrating various cable circuits wherein the disturbing and signal-distorting eflects with reference to the coil 16* of the receiving galvanometer are counterbalanced by means associated with the siphon recorder or other receiving instrument, and whereby a shunted condenser of greater capacity than has been practicable heretofore may be employed in connection with the receiving coil 16. Fig. 39 shows diagrammatically the provision of condensers and inductive resistance in shunt relation with respect to the windings of the coil 10 (Fig. 2) of the siphon recorder or other receiving or retransmitting instrument. Fig. 40 is a diagram illustrating the use of a plurality of sources of illumination in series relation. Fig. 41 illustrates more or less diagram matically the operation of a primary actuating device by the diapl'iragm of a telephone or phonograph or like instrument. Fig. 42 is a' diagram illustrating, :1 development of the lens and reflector arrangement shown in Fig. 1 to derive light pencils from all sides of a single source of illumination.

Referring now to the drawings, and first to Figs. 1 and 2: Numeral 1 designates a primary actuating device, for example, the movable reflector or mirror of a reflecting galvanometer. or telephone or phonograph diaphragm, etc, and 2 designates a radio-electro-sensitive de vice. for example, a selenium cell or group the motions of the light beam controlled by actuating device 1. 3 designates a source of illumination, 4% a series of primary con- (lensing lenses. arranged in a semi-circle around the light 3 so as to be equi-distant therefrom, each of these condensing lenses being asection or strip taken from the center of a spherical condensing lens, preferably a plano convex lens, as shown in detail in Figs. 3 and 4. or a meniscus lens, 4", as shown in F igs. 7 and 8. 5-5 designate a series. of primary reflectors, preferably prisms. adapted'to deflect at proper angles pencils of light from the condensing lenses 4 through the secondary condei'isiug lenses (5-6 upon the primary actuating device 1; and 7 designate.a group of secondary reflectors, also preferably prisms, adapted to 35 shows a side elevaby reflection. -.is shown in Fig. 11.

' are arranged in a series occupying approxia mirror actuated by the primary reflect beams or light coming from the several primary reflectors 5, and from the pri mary actuating device 1, upon the radioelectro-sensitive device 2. For simplicity of illustration, the several pencils of light 8-8 are indicated, in Fig. 1, each by a single dotted .line representing the axis of the corresponding pencil of light. For various practical reasons, I prefer to employ light beams, or pencils, which are of rectangular section and are relatively narrow, i.

6., the height of which is much greater than their breadth, or vice versa.

In Fig. 2 I illustrate in front elevation two radio-electro-sensitive devices 2, and a cross-section of the light beams 8 at the point where they impinge coincidentally on the surface of the radio-electro-sensitive devices 2. Primary lenses 4 are so arranged that the pencils of light are projected divergently relatively, and by means of the primary reflectors 5 these relatively divergent pencils are then brought together on the primary actuating reflector 1, each at a definite angle with respect to the other pencils. It will be obvious that the beams 8 might be deflected by refraction through prisms in lieu of reflection, but since such refraction, even where achromatic prisms are employed, involves more or less disper sion, I prefer in general. to deflect the beams Such a refraction apparatus In Fi 1 the primary condensing lenses 4 niately one-half of the the source of illumination 3. light from the space surrounding To utilize the other half of the space surrounding the source of illumination, I have provided reflectors 9-9, '(also shown in Figs. 5 and 6) which in practice are segments of spheres, and reflect forward the light reaching them from the source of illumination. so that the light from all sides of the source of illuminationis utilized.

In the operation of this apparatus shown in Fig. l. the various light pencils 8 pro-. jected by the condensing lehses at, through the primary reflectors 5 and secondary condensing lenses 6., are concentrated upon the primary actuating device 1, and are. reflected therefrom as pencils 8 in divergent paths to the corresponding secondary reflectors 7, and thence are concentrated as pencils 8" upon the .radio -elcctro-sensitive devices 2. 120 fllfl' slltt movement of the primary actuating thi ice. 1 t and all movements of that primary actuating device are'small) pro dare corresponding movements of the reflected light pencils 8. the movement of these reflected pencils in practice. however. being so small that they do not, p as out of the fields of their respective idary reflectors 7: and from these secondary reflectors T, the further reflected pencils of light 130 8* concentrated upon the radio-electro-sensitive device 2, move across the surface of that radio-electro-sensitive device, in accordance with the movements of the primary actuating device 1. As shown particularly in Fi 2. such movements of the pencils of light vary the illumination of the two radioelectro-sensitive devices 2 in opposite senses. i. 0., increase the illumination of one of such radio-electro-sensitive devices, and simultaneously decrease the illumination of the other. thereby decreasing the electrical resistance ot' the one radio-electro-sensitive device and increasing the electrical resistance of the other radio-electro-sensitive de vice. and so causing movement of the receiver coil 10, such coil 10 being in the field of force produced by the magnet poles 1l ll. It will be observed that although a large number of separate, pencils of light are derived from the same source of illumination yet since these pencils of light are all concentrated upon the same radio-electro-sensitive devices. the effect of movement of the primary actuating device 1, with re spect to the receiver coil 10, is the summa tion of the efi'ects of the individual pencils of light; that is to say. the movementof each individual pencil of light has the same ctl'ect. in causing deflection of the receiver coil 10, that that movement would have if none of the other pencils of light were present: but the combined eflect of the movements of the various pencils of light is the summation of the effects that each individual pencil of light would cause.

The receiver coil 10 is a double coil. c0mprising two independent windings, (see Fig. 2"), one in circuit with one electro sensitive device 2, the other in circuit with the other. electro-sensitive device 2, the two windings of the coil 10 neutralizing each other when the current strengths in both coils are the same. Increase of resistance of one radioelectro-sensitive device, and decrease of resistance of the other radio-electro-sensitive device. therefore. produces a combined eti'ect in the two windings of the receiver coil 10, substantially equal to twice the detlective effect that variation of resistance of one radioelectro-sensitive device 2 only would cause. I have indicated a torsional mminting for the receiver coil 10. comprising two lower suspension fibers 12. and a single upper sus pension fiber 13. l'lowever, the particular method of suspension of the receiver coil is not material to the present invention.

The size of the condensing lens image tormed. by any one pencil ot' light, at the radio-electro-sensitive devices 2, is determined by the size and focus of the corresponding primary condensing lens 4. the focal length" of the secondary condensing lens (3 through which the beam passes. and the total length of the beam from the primary condensing lens to the radio-eleetrd sensitive devices 2. In the arrangement shown in Fig. l. the beams projected from the light source 3 to the primary actuating device 1 at the smaller angles have less total length than those projected at the larger angles; and in order that the lens images shall be uniform 0' approximately of uniform size and as perfectly defined. as possible, the secondary condensing, lenses 6 for the shorter pencils of light are of shorter focus than those of the longer pencils. and are placed correspondingly closer to the pri' mary actuating device 1. With this arrangement, and with proper adjustment, the several beams may be made of uniform cross section at the point of final impingement on the radio-electro'sensitive devices al though the images of the illuminant projected by the longer pencils on the reflector 1 are somewhat larger than the images of the illuminant projected by the shorter pen cils. .l prcter to employ primary condclning lenses 4 of the same focal length. and of a shorter focal length than that of any of the sccondanv condensers l. this arrangement permitting the primary condensing lenses to be placed at the smallest practical distance from the illuminant. so that each receives the maximum amount of light.

In Fig. 9 I have shown an arrangement in many rcsi'iects similar to Fl 1. wherein the secondary condensing lens as. there designated bv numerals (9, are of the same focal length. an intermwliate series of reflectors it being interposed. between. the primary re flectors 5 and the secondary condensing le ses 6 In this arrangement shown in Fig. 9, the lengths of the various pencils of light tromthe source of illumination to the primary actuating device 1 are the same: the intermediate series of reflectors ll being used in order that such may be the case. In Fig. 5) I have also indicated the use of mirror reflectors 7 in lieu of the prism rcflectors T of Fig. 1.

Instead of employing, as in Figs. 1 and 9. a large number of small segmental primary condensing lenses 4 4. I may employ a lesser number of larger primary condensing lenses, each such condensing lens serving for a plurality of pencils of light. Such an arrangement is shown in Fig. 10. wherein I- have shown two primary condensing lenses 4-4, the light beam through each of these condensing lenses being divided into a numher of separate pencils by reflectors M 3. One secondary condensing lens. (3. is shown for all of these pencils of light. the light pencils from one of the condensers 4 being reflected through this secondary condenser ll directly from the reflectors 5: while the pencils of light from the other condenser l are reflected through the secondary condenser ti" by means of an intermediate re- 

